Anatomical Configurations of Dominant Anastomotic Veins of the Superficial Cortical Venous System

Understanding the anatomy of the anastomotic veins (AV) of the superficial cortical venous system (SCVS), viz. superficial Sylvian vein (SSV) - also known as the superficial middle cerebral vein; vein of Labbe (VL) and vein of Trolard (VT), are imperative for neurosurgical procedures. This study aimed to investigate variant anatomical patterns of dominance of the AV, to elucidate the haemodynamically balanced SCVS, by reporting variations between the presence, diameter and dominant patterns of the AV. Two hundred lateral angiograms were included, depicting left and right cerebral hemispheres of the same patient (n = 100 patients). Angiograms were analysed and variations recorded. Results were statistically compared against laterality, age, sex and ethnicity. Presence of the VL had the highest occurrence (96.5%), whereas the SSV and VT had an occurrence of 75.5% and 64.5%, respectively. This study reports presence of double veins of the AV: SSV (12.0%), VL (22.0%) and VT (19.5%). Furthermore, presence of a triple vein for each AV is reported. Diameters for the SSV, VL and VT were 1.99 ± 0.500mm, 2.18 ± 0.579mm and 2.14 ± 0.472mm, respectively. Statistically significant relationships were established between diameters and the SSV, VL, VT and VT2 (double VT). Seven types of dominant patterns were recorded: Equilibrium; singular dominance of SSV, VL and VT; co-dominance of SSV/VL, SSV/VT and VL/VT. The Equilibrium dominant pattern of drainage had the highest occurrence (54.5%). Patterns of dominance of these AV can aid the neurosurgeon in curbing the risk of iatrogenic injury and postoperative infarcts even after an otherwise successful surgery.

Intra-arterial onyx embolisation of sphenobasilar sinus fistula using pressure cooker technique: case report and review of the literature

Dural arterio-venous fistulas of the middle cranial fossa may occur within the dura of lesser or greater sphenoid wings. Lesser sphenoid wing fistulas rarely recruit cortical venous drainage and mostly drain in the cavernous sinus. On the other hand, greater sphenoid wing dural fistulas, also known as paracavernous fistulas or sphenobasilar and sphenopetrosal sinus fistulas, are much more notorious as they almost always connect with the superficial middle cerebral vein resulting in secondary cortical venous reflux and varix formation. Curative transarterial or transvenous endovascular embolisation of fistulous connection is the primary therapeutic strategy, particularly using onyx via the transarterial approach. In the present case we describe a 62-year-old man who presented with significant subarachnoid haemorrhage, intraparenchymal and intra-ventricular bleed. Digital subtraction angiography showed a middle cranial fossa dural arteriovenous fistula in the region of the sphenobasilar sinus with cortical venous reflux and varix formation. The patient underwent successful transarterial endovascular embolisation with complete elimination of the fistula using onyx 34, onyx 18, squid 12 and a Scepter XC balloon using the pressure cooker technique. We also report the development of facial nerve palsy due to inadvertent reflux of onyx in the petrosal branch of the middle meningeal artery.